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How To Find A Water Leak (Complete Guide)

Finding A Water Leak

Finding a water leak in your home may sometimes be simple. An easy check underneath the kitchen sink could reveal the leak and type of repair needed. But this is not always the case.

Often, we find ourselves stuck on where water is leaking from or asking ourselves why our water bill is so high. Consistent water leaking can lead to cosmetic damage, structural damage, termites, mold, and more. So you must find the source and repair it as soon as possible.

In this post, I am going to offer a complete guide in finding your water leak. Let’s get started.

Determining If You Have A Water Leak

The first step in finding a water leak is making sure you have a water leak in the first place. While you see water damage on your home, it may not be from the plumbing system, but rather exterior water entering the home.

For example, you could have a roof leak, a crack on your home’s exterior, or a drainage issue. So, the first step is checking your water meter.

Checking Your Water Meter

You will want to check your water meter to see if there is movement while all water fixtures are off. To do this, turn off all water fixtures within your home. This could be:

  • Hose Bibs
  • Sink Faucets
  • Dishwashers
  • Washing Machines
  • Showers
  • Toilets – Make sure nobody flushes the toilet during the test.

Then, go to your water meter and see if the gauge is moving at all. If the gauge is moving, you have a water leak somewhere or a running toilet. If the water meter is not moving, you may have a water leak from water drainage pipes or the exterior environment.

Check out our water intrusion category to read about how water can enter your home from the exterior. Keep reading to learn about water leaks from drainage pipes.

Keep in mind that it is possible to have water leaking into your home from your floors. Our friends over at Boggs Inspection Services wrote a nice article about finding a water leak underground you should check out.

Let’s dig into finding that water leak.

Finding The Water Leak

More likely than not, if you are reading this post, you have an idea of where the water leak could be. If not, have no fear, we are here!

In the sections below, we will list the common and uncommon places you should check for water leaks. Feel free to skip to the sections that relate to your case. If you are unsure of where to start looking, we can help there too. Just read all the areas noted below and take the steps noted.

Common Areas For A Water Leak

Let’s start first with the most common areas for a water leak.

Undersink Diagram - Water Leaking at drainage pipe

Under Sinks

It’s quite common to have water leaking underneath your sink. It would be best if you start by checking under and around each sink. Be sure to rub your hand against/around the P-Trap, supply valves, and all connections to check for water. You can also check the bottom of the cabinet or around the cabinet for water damage.


Toilets are another common place for leaks to occur. Check around the floor, at the tank to bowl connection and the supply valve.

Your toilet could also be constantly running, meaning the toilet is constantly flushing. Sometimes the flush could be a slow drip, so be sure to listen for water trickling. If your toilet is constantly running, you can replace the interior tank components.

Dripping Faucets & Showerheads

This one is fairly simple. Check all your showerheads, sinks, and exterior hose bibs to see if the water is slowly dripping.


Check underneath the fridge, washing machine, and dishwasher to see if water may be leaking on the floor. You can also check the wall where the water supply is coming from to see if the valve/pipe is leaking at the wall.

Water Heater

Lastly, check around the water heater for leaks. You can check the top valves, the floor, and pipes connecting to the water heater.

Water Leak From Plumbing Supply Line Underneath The Floor

Uncommon Areas For Water Leaks

Uncommon areas for water leaks can be difficult to find and usually leave clues to investigate further. For example, if you see mold growth on a wall, you might think there is a water leak behind it. On the other hand, this could be due to high humidity in the environment.

Here are a few uncommon areas to check:

  • Attic – Check for water stains or wet insulation.
  • Floor – Check the floor for warping or staining.
  • Walls – Check walls for warping, paint, or damaged drywall.
  • Crawlspace – Crawl through your crawlspace (if you can do so safely and feel comfortable with it) to check for water leaks at drainage or supply pipes.

However, investigating further may require minor demolition, special tools, or unique insights. For example, check out pinhole leaks in copper pipes to see how small water leaks under homes could be discovered.

Special Tools To Find Water Leaks

Home inspectors use unique tools to help them find water leaks. You could use these to help you find water leaks, but some tools take special training to use.

Hygrometer – A hygrometer detects humidity levels in a home. A humid environment could indicate many issues, such as an improperly functioning air conditioner or a heavy water leak.

Thermal Imaging – Thermal cameras detect surface level temperature differentials. When using a thermal camera, home inspectors evaluate the temperature differentials and inspect for water evaporation. As water evaporates, the water is cooler to the relative air temperature, therefore, showing a cold spot on the camera. Areas that show evidence of water leaks from a thermal camera should always be verified by a moisture meter or seeing the physical leak.

Moisture Meter – Moisture meters can be used to detect the level of moisture in a material. The meter sends electrons through the surface it is in contact with, so if there is a high level of water, the electrons easily conduct through the surface. A word of caution, though, a metal surface would be highly conductive, and therefore, not give an accurate representation of a wet/dry surface.

Next Steps

If you checked the common areas and are still struggling to find the water leak, do not be afraid to call a home inspector. Home inspectors have many other tools and building knowledge to help you find the water leak. Home inspectors can also give you action steps on what to do next, such as having a full plumbing system evaluation by a licensed plumber.

Have a question? Drop a comment below!